Chronic eosinophilic pneumonia. Evidence for eosinophil degranulation and release of major basic protein

A patient with chronic eosinophilic pneumonia associated with ulcerative colitis and asthma is described. Exacerbations and remissions of these disorders paralleled each other. Pleural fluid and lung tissue contained high levels of eosinophil granule major basic protein, a substance with toxic effects on cells and tissues. The results indicate that eosinophils degranulate in the lung in eosinophilic pneumonia and point to the possibility that granule constituents damage lung tissue in the course of the disease.